World number two Alexander Zverev beat Cameron Norrie 7-6 (7/1), 6-4 to kick-start his bid for the China Open on Thursday.
The 29-year-old is the top seed in Beijing after world number one Jannik Sinner, the reigning champion, withdrew due to injury.
Zverev hit 15 aces but did not have it all his own way against Norrie, ranked 40th, who had some joy pushing the German around the court.
The Briton came within a point of winning the first set, but the US Open champion closed out the game and capitalised in the tie-break when Norrie fired long.
Zverev was similarly clinical in the second set, which followed serve until he broke Norrie in the 10th game to take match point at the first time of asking.
He will play either Shang Juncheng of China or Sebastian Baez of Argentina in the second round.
"I'm really surprised and really happy with how I played," said Zverev, who only arrived in China from Europe two days ago after helping Team Europe to the Laver Cup.
Earlier, Russia's Roman Safiullin upset Italy's Flavio Cobolli, brushing aside the Roland Garros finalist 6-3, 6-2 to set up a second-round tie against either Tallon Griekspoor or Andrey Rublev.
In the women's draw, Zheng Qinwen needed two hours and 44 minutes to hold off world number 231 Shi Han in the first round, beating her compatriot 7-6 (8/6), 4-6, 6-2.
Both women struggled to win points on the sun-baked side of a split-screen court, but the Paris Olympic champion fought through 44 unforced errors to earn a meeting with Russia's Anna Kalinskaya.
Zheng, the current world number 54, has struggled with form since needing elbow surgery last year, although she made the US Open quarterfinals as a qualifier.